Method of forming phonograph records



Apsrifl 23, 1936. F. c. BARTON W Q METHOD OF FORMING PHONOGRAPH RECORDS Filed Sept. 50, 1932 Eigfi.

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Patented Apr. 28, 1936 UNITED STATES PATENT OFFICE METHOD OF FORMING PHONOGRAPH RECORDS Application September 30, 1932, Serial No. 635,538

8 Claims.

My invention relates to phonograph records and, more particularly, to disc records of the laminated type and the method of forming such records.

Phonograph record discs of this type have been formed in several ways. For example, according to one method, a suitable base material is coated, on either one or both faces, with a surface material in which the sound grooves are formed. The surface material may be in the form of a varnish or the like and, after the base is coated, the record is dried, out out, and the sound groove formed therein. According to another method, the surface layer or layers may be attached to the base by means of a suitable adhesive, after which the built-up record is also dried, out out, and, subsequently, pressed or cut to provide a sound groove therein. These and other methods all require more or less processing entailing a number of operations which are both time and labor consuming, as well as being expensive.

I have found that it is possible to apply the record material directly to the base material and to cause the two to adhere to each other under the action of heat and pressure without the use of additional adhesive. Thus, the record pressing operation may be also employed to advantage in causing the record material to adhere to the base material, since the pressing operation is performed with a heated die or matrix and in this way, I am able to attain the primary object of my invention, namely, to produce a laminated disc record for phonographs by a method which is not subject to the disadvantages present in the methods heretofore employed for this purpose.

Another object of my invention is to provide an improved method of producing laminated phonograph record discs with a minimum of operation.

Still another object of my invention is to provide an improved method of producing doublefaced, laminated phonograph record discs of uniform thickness.

A further object of my invention is to provide an improved method for producing double-faced, laminated phonograph record discs wherein the surface layers in which the sound grooves are formed will be of uniform thickness.

Still a further object of my invention is to provide an improved method of forming flexible laminated record discs.

And another object of my invention is to provide an improved method of producing laminated phonograph record discs which is eflicient and economical, and which is well adapted to rapid quantity production,

The novel features of my invention are set forth with particularity in the appended claims. The invention itself, however, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment, when read in connection with the accompanying drawing, in which Fig. 1 illustrates one step in the method of forming a laminated record disc according to my invention,

Fig. 2 illustrates a similar, but subsequent, step to that illustrated in Fig. 1,

Fig. 3 shows, in elevation, a laminated record disc that might result from combining the two steps of Figs. 1 and 2 in a single step, and

Fig. 4 shows, in elevation, a laminated record disc formed by the two individual steps of Figs. 1 and 2.

Referring, now, to the drawing, wherein similar reference numerals indicate corresponding 1 parts throughout, I have shown a core member I which forms the base material of the record disc and which may be of paper, cardboard, fibre board, sheet metal, or any other material. Preferably, I employ calendered cardboard, but any suitable sheet material may be employed, this ma terial being flexible, of course, when it is desired to form a flexible record.

In forming a laminated record according to my invention, the base material I is placed upon a hard, rigid, backing plate or support 2 which may be set, for example, in the bottom die holder of the usual record press, the base member I being threaded upon the pin 3 of the die holder so as to be centered thereon. A biscuit 4 of any suitable record material and of materially greater thickness but of much less surface area than the base member I is then placed on the base member I substantially centrally thereof, and a heated die or matrix 5 is pressed down thereon until its central aperture 6 snugly engages the protruding end of the pin 3. When the record has been pressed, the record material 4 is allowed to cool and set, whereupon it is removed from the press and the edge thereof finished 01f in the usual and well known manner.

The record material of which the biscuit 4 is formed should be of such a nature that the application of heat thereto will render it plastic, so that, as the matrix 5 is pressed down thereon, it will flow in all directions and be spread out or distributed over the entire surface of the base material I. While any suitable record material may be employed, I preferably employ a resinous composition having a base of chlorethylene, or

vinyl chloride, as I have found that a resin of this type will readily adhere to the cardboard base under the action of heat and pressure. Thus, the single, customary record pressing operation commonly employed in the manufacture of commercial records may be availed of to bring the record material 4 and the base material I into intimate adhering relation, and, because the base material I is backed up by the rigid plate 2, the uniform pressure exerted by the matrix 5 will cause the biscuit 4 to be uniformly distributed over the base material I to form a coating or surface layer of uniform thickness.

The procedure described above in connection with Fig. 1 will, of course, produce only a single faced record. When it is desired to produce a double faced record, a biscuit of record material could, for example, be placed directly on the plate 2 which, in this instance, would be a record matrix similar to the matrix 5, a sheet of the base material or core member I superposed thereon, and a second biscuit of the record material placed on top of the core member. Upon pressing down the matrix 5, both biscuits would be distributed over the core member, one over each face thereof, and both faces of the record would be produced simultaneously. However, since the lower biscuit becomes plastic and the core member I is not backed up by a rigid support, there is nothing to insure an even distribution of the record material over the faces of the core, and it is quite possible that a record such as that illustrated in Fig. 3 would result.

It will be noted that, in this record, the surface layer 4a, resulting from the lowermost biscuit 4,'is thicker at the left hand end than at the right, while the surface layer 41) resulting from the upper biscuit 4, is thicker at the right hand end than at the left, the core member I being embedded in the record at an angle to the planes of the outer surfaces of the layers 4a and 412. While each surface of a record so formed has suflicient thickness to receive sound vgroove impressions at the thicker portion thereof, it is subject to the serious disadvantage that the thinner portion thereof may be entirely too thin to receive sound groove impressions without having the impressions extend through into the core. This, of course, impairs the reproducing qualities of the record.

In order to eliminate this difiiculty, and to insure the formation of a double faced record with surface layers of uniform thickness throughout, I prefer to form each layer individually. Accordingly, the core member I is first provided with a surface layer 4a of uniform thickness throughout in the manner heretofore described with reference to Fig. 1, the die 5, however, being a flat plate or disc, instead of a record matrix, so that the surface 4a will be perfectly smooth instead of indented with sound grooves. After the surface layer 411 has become set, the disc is transferred to a record matrix I with the surface layer 4a thereof resting on the matrix I, and the disc threaded on the pin 8. A second biscuit 9 of the record material is then placed on the now upper face Ia. of the core member I, substantially centrally thereof, and a second record matrix I0 pressed down thereon, both matrices 'I and I 0 being heated. By the time the matrix III has been brought down sufliciently for its aperture II to snugly engage the pin 8, the biscuit 9 will have become plastic and distributed uniformly over the surface of the core member I and, since the disc is resting on the rigid support provided by the matrix I, the surface layer 9a, resulting from the biscuit 9, will be uniform throughout in its thickness. At the same time, the matrices 1 and II! will impress sound grooves in the surfaces 411 and 9a, respectively, and this, obviously, will be done simultaneously with the step of rendering the biscuit 9 plastic and distributing it uniformly over the core member I.

As will be clear from Fig. 4, the finished double faced record R resulting from the last described process is uniform throughout in thickness and the core member I is embedded therein in a plane parallel to the planes of the outer faces of the surface layers 4a and 9a. Each of the layers 4a and 9a may be of the same thickness, or of different thicknesses, as desired, this depending entirely upon the adjustment of the matrices I and Ill relative to each other. In any event, however, the surface layers 4a and 9a should be uniform in thickness throughout, whether they are both of the same thickness or not.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. For example, where a double faced rec ord is to be formed of a thermosetting instead of a thermoplastic material, the surface layer 4a may be provided with sound grooves just as in the case of a single face record, since the heat and pressure developed in the second pressing operation of Fig. 2 will have no effect on the surface 4a. once it has become set. Many other modifications will readily suggest themselves to those skilled in the art. is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. The method of forming a flexible laminated record disc which comprises first placing a flexible base material on a rigid support, applying a record material to the then upper face of said base material, causing said record material to spread out substantially uniformly over and cover said face of the base material, causing said spread-out record material to adhere to said base material, and finally reversing said coated material and repeating said steps upon the other face thereof whereby to form a double faced record disc.

2. The method of forming a flexible, doublefaced. laminated record disc which comprises placing-a flexible base material on a rigid support, applying a biscuit of record material to one face of said base material, causing said record material to spread out substantially uniformly over said face of the base material, causing said spread-out record material to adhere to said face of the base material, reversing the disc, replacing the disc upon a rigid support with the second face of said base material upward, applying a second biscuit of record material to said second face of the base material, causing said second biscuit of record material to spread out substantially uniformly over said second face, and causing said latter spread-out record material to adhere to said second face of the base material.

3. The method of forming a disc sound record which comprises applying a biscuit of thermoplastic record material to a sheet of base material, simultaneously rendering said record plastic and distributing it substantially uniformly over one face of said base material whereby to form My invention, therefore,

a surface layer of record material on said face of the base material, causing said surface layer to become set, applying a second biscuit of said thermoplastic material to the second face of said base material, simultaneously rendering said second biscuit plastic and distributing it substantially uniformly over said second face of the base material whereby to form a surface layer of record material on said second face, and forming sound grooves in both said surface layers.

4. A method according to claim 3 wherein the sound grooves are impressed in said surface layers substantially simultaneously with the step of rendering the second biscuit plastic.

5. A method according to claim 3 wherein the first surface layer is again rendered plastic while said second biscuit is being rendered plastic and is being distributed over the second face of the base material, and wherein the sound grooves are simultaneously impressed in both said surface layers while said layers are in plastic condition.

6. In the method of forming a laminated disc sound record, the steps which consist in substantially uniformly distributing a mass of record material over one face of a core member the opposite face of which carries a preformed coating of record material, and impressing sound grooves in said preformed coating simultaneously with the step of distributing said record material over said core member.

'7. In the method of forming a double faced disc sound record, the steps which consist in preforming first one surface thereof and then forming the other surface thereof, and impressing sound grooves in the first surface thereof while simultaneously forming said other surface.

8. In the method of forming a double faced disc sound record, the steps which consist in preforming first one surface thereof and then forming the other surface thereof, and impressing record grooves in both said surfaces while simultaneously forming said other surface.

FREDERICK C. BARTON. 

